Installing a Balance Staff that looks different than the Original

[jdrichard]

I’m doing a job for a gent on a BW Raymond 16S Elgin 21 Jewel and I have noticed that the new balance he sourced is the same length, but the balance shoulder and seat seem to ba a bit off. Included some disassembly photos. Plus the last guy shellacked the heck out of the roller jewel. Not sure why and I may need to clean this up....can’t let it go; darn!

[Poljot]

1 hour ago, jdrichard said:

I’m doing a job for a gent on a BW Raymond 16S Elgin 21 Jewel and I have noticed that the new balance he sourced is the same length, but the balance shoulder and seat seem to ba a bit off. Included some disassembly photos. Plus the last guy shellacked the heck out of the roller jewel. Not sure why and I may need to clean this up....can’t let it go; darn!

He or SHE shellacked it because shoulder dia was too small and roller could not be secured on the staff. Right?

And because this is a double roller - more shellac is "better"... 

Nice photos and great tools!

Edited December 26, 2020 by Poljot

[jdrichard]

59 minutes ago, Poljot said:

He or SHE shellacked it because shoulder dia was too small and roller could not be secured on the staff. Right?

And because this is a double roller - more shellac is "better"... 

Nice photos and great tools!

So I might have the same problem when putting in the new balance staff.

[Poljot]

1 hour ago, jdrichard said:

So I might have the same problem when putting in the new balance staff.

Well, only time will tell

I would try (by hand) the roller on your new staff to see if it's loose, or not. Are you able to  make a new Staff?

 

Edited December 27, 2020 by Poljot

[jdrichard]

2 hours ago, Poljot said:

Well, only time will tell

I would try (by hand) the roller on your new staff to see if it's loose, or not. Are you able to  make a new Staff?

 

Yes I can. Made a few but not often.

[JohnR725]

14 hours ago, jdrichard said:

BW Raymond 16S Elgin 21 Jewel

I don't suppose you give me the staff number so I can looked up something?

[rodabod]

The original staff looks like it has a proper back-slope to help prevent oil spreading. I’m sure the new one will be fine without. 
 

From what I can see from your comparison photo, it’s hard to tell if the balance rim (and therefore hairspring) will remain at the same height. Can possibly address that later if there is an issue. 
 

Bear in mind that the excess shellac on the roller may in fact be holding it together if it is split. 

[jdrichard]

2 hours ago, rodabod said:

The original staff looks like it has a proper back-slope to help prevent oil spreading. I’m sure the new one will be fine without. 
 

From what I can see from your comparison photo, it’s hard to tell if the balance rim (and therefore hairspring) will remain at the same height. Can possibly address that later if there is an issue. 
 

Bear in mind that the excess shellac on the roller may in fact be holding it together if it is split. 

You are perhaps correct. If that is so, I will need to source another roller table. Or figure something out. Not sure if I can make a roller table on my lathe...but anything is possible.

[JohnR725]

One of the problems with fitting balance staffs especially American pocket watch is they often came in variations. Not only variations but oftentimes variations with the exact same part number. Then aftermarket replacement staff's didn't always dimension exactly the same as the original just to make things more interesting. If you give me a serial number I can look up and get the dimensions of the original staff for you?

[jdrichard]

6 hours ago, JohnR725 said:

One of the problems with fitting balance staffs especially American pocket watch is they often came in variations. Not only variations but oftentimes variations with the exact same part number. Then aftermarket replacement staff's didn't always dimension exactly the same as the original just to make things more interesting. If you give me a serial number I can look up and get the dimensions of the original staff for you?

This is the staff it is suppose to be based on the movement SN.

[JohnR725]

The good news is there appears to only be one staff with that number in three different pivots sizes. But the bad news is the staff number you have above is a bestfit staff although it's not entirely bad as you have lathe as there usually oversize.